WCF Error "This could be due to the fact that the server certificate is not configured properly with HTTP.SYS in the HTTPS case"

We had this issue as the host server had been updated to use TLS V1.2 and we were connecting using standard SSL. This was an update made as part of pen testing of the sites. We saw the issue in code connection, but not browsers going to the wsdl.Below code resolved:

if (System.Net.ServicePointManager.SecurityProtocol == (SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls))    System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;

Taken from here: How do I disable SSL fallback and use only TLS for outbound connections in .NET? (Poodle mitigation)

I Had the same issue on a service running on IIS 7the service connects to multiple suppliers servers (some SSL some not)when adding a new one of these (this new supplier was TLS 1.2) I would get the error after a few requests were made to the original servers (SSL).

To confirm this I simply logged the System.Net.ServicePointManager.SecurityProtocol before each request to each supplier.

Low and behold after restarting the service (or restarting the application pool) I would get the output Ssl3, Tls but after a few requests to the original supplier servers this changed to Ssl3 and requests to the TLS service gave the error.

To fix I simply did what user369142 suggested. Before each request to the new server:

System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12 | SecurityProtocolType.Ssl3;

and no more errors.

In my case I had to enable SchUseStrongCrypto for .NetThis forces the server to make connection by using TLS 1.0, 1.1 or 1.2. Without SchUseStrongCrypto enabled the connection was trying to use SSL 3.0, which was disabled at my remote endpoint.

Registry keys to enable use of strong crypto:

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NetFramework\v4.0.30319]"SchUseStrongCrypto"=dword:00000001[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319]"SchUseStrongCrypto"=dword:00000001